Chromosome 3 is 7% of the human genome and encompasses 210 megabases of DNA. Despite its size, chromosome 3 has been slow to accumulate markers. Recently, a large number of new markers have been generated for chromosome 3, as evidenced by the number of DNA segments assigned to chromosome 3: at HGM9 there were only 29 single copy DNA segments and at HGM10 there were 114 firmly assigned markers. Consequently, now we will be able to begin to construct maps for chromosome 3. The purpose of this workshop is to consolidate data from many labs to construct physical, linkage and radiation maps for chromosome 3. These maps will establish the common bases for the maps, identify overlap, and identify areas that need resolution. The workshop will be two days in February, 1990 at the University of Texas Health Science Center at San Antonio. The structure of the meeting will be a series of short presentations by each of the 27 laboratories involved followed by an intense working session to resolve inconsistencies in the map and to produce consensus maps. Relevant material generated at this meeting will be presented to the chromosome 3 committee for HGM10.5 and HGM11 for their use in generating a report.